package com.inforich.app.utils;

/**
 * @description: some desc
 * @author: HJM
 * @date: 2023/7/5
 */

import org.springframework.web.multipart.MultipartFile;
import sun.misc.BASE64Decoder;

import java.io.*;

public class BASE64DecodedMultipartFile implements MultipartFile {

  private final byte[] imgContent;
  private final String header;

  public BASE64DecodedMultipartFile(byte[] imgContent, String header) {
    this.imgContent = imgContent;
    this.header = header.split(";")[0];
  }

  @Override
  public String getName() {
    // TODO - implementation depends on your requirements
    return System.currentTimeMillis() + Math.random() + "." + header.split("/")[1];
  }

  @Override
  public String getOriginalFilename() {
    // TODO - implementation depends on your requirements
    return System.currentTimeMillis() + (int) Math.random() * 10000 + "." + header.split("/")[1];
  }

  @Override
  public String getContentType() {
    // TODO - implementation depends on your requirements
    return header.split(":")[1];
  }

  @Override
  public boolean isEmpty() {
    return imgContent == null || imgContent.length == 0;
  }

  @Override
  public long getSize() {
    return imgContent.length;
  }

  @Override
  public byte[] getBytes() throws IOException {
    return imgContent;
  }

  @Override
  public InputStream getInputStream() throws IOException {
    return new ByteArrayInputStream(imgContent);
  }

  @Override
  public void transferTo(File dest) throws IOException, IllegalStateException {
    new FileOutputStream(dest).write(imgContent);
  }

  /**
   * base64转MultipartFile文件
   *
   * @param base64
   * @return
   */
  public static MultipartFile base64ToMultipart(String base64) {
    try {
      String[] baseStrs = base64.split(",");

      BASE64Decoder decoder = new BASE64Decoder();
      byte[] b = new byte[0];
      b = decoder.decodeBuffer(baseStrs[1]);

      for (int i = 0; i < b.length; ++i) {
        if (b[i] < 0) {
          b[i] += 256;
        }
      }

      return new BASE64DecodedMultipartFile(b, baseStrs[0]);
    } catch (IOException e) {
      e.printStackTrace();
      return null;
    }
  }
}